But even amid the craziness — the SEC has suspended trading until July 24 after “potentially manipulative transactions” — there are some worthwhile takeaways for investors.

“Cynk has a paper value of $6 billion. The stock has rallied more in the last three weeks than Apple has since their IPO 34 years ago. Beyond my mocking, there’s an important lesson here,” Eddy Elfenbein, individual investor and Crossing Wall Street blogger, wrote Thursday evening. “Those of us who force rationalism and sobriety on the market are engaged in a constant war, and we’re not always winning.

“The suckers are out there,” he added. “Who knows how garbage like Cynk gets going? Once people start buying it, the irrational exuberance mentality builds on itself. Soon people bid it up simply because they think the stock will go up, which in turn causes more people to buy…which in turn causes the stock to go up.”

No, Cynk’s trading isn’t the sign of a market bubble. Instead it’s the product of some “potentially manipulative transactions” focused on one stock rather than the broad market. Sure, it’s crazy and it doesn’t make much sense. But that, in itself, offers an important reminder of how the market can work.

“Remember, there are lots of finance professors today who tell us how efficient the market is, who say that the market is rational and that it’s impossible for an investor to beat the market over the long haul. Please. The market is made of humans, and it has all our virtues and vices,” Mr. Elfenbein says. “The rally in Cynk Technologies is a perfect example.”